Last updated on November 14, 2020 by Dan Nanni
In the world of Linux, adoption of
systemd has been a subject of heated controversy, and the debate between its proponents and critics is still going on. As of today, most major Linux distributions have adopted
systemd as a default init system.
Billed as a "never finished, never complete, but tracking progress of technology" by its author,
systemd is not just the init daemon, but is designed as a broader system and service management platform which encompasses the growing ecosystem of core system daemons, libraries and utilities.
One of many additions to
systemd-networkd, which is responsible for network configuration within the
systemd ecosystem. Using
systemd-networkd, you can configure basic DHCP/static IP networking for network devices. It can also configure virtual networking features such as bridges, tunnels or VLANs. Wireless networking is not directly handled by
systemd-networkd, but you can use
wpa_supplicant service to configure wireless adapters, and then hook it up with
On many Linux distributions, Network Manager has been and is still used as a default network configuration manager. Compared to Network Manager,
systemd-networkd is still under active development, and missing features. For example, it does not have Network Manager's intelligence to keep your computer connected across various interfaces at all times. It does not provide
ifup/ifdown hooks for advanced scripting. Yet,
systemd-networkd is integrated well with the rest of
systemd components (e.g.,
resolved for DNS,
timesyncd for NTP,
udevd for naming), and the role of
systemd-networkd may only grow over time in the
If you are happy with the way
systemd is evolving, one thing you can consider is to switch from Network Manager to
systemd-networkd. If you are feverishly against
systemd, and perfectly happy with Network Manager or basic network service, that is totally cool.
But for those of you who want to try out
systemd-networkd, you can read on, and find out in this tutorial how to switch from Network Manager to
systemd-networkd on Linux.
systemd-networkd is available in
systemd version 210 and higher. Thus distributions like Debian 8 Jessie (
systemd 215), Fedora 21 (
systemd 217), Ubuntu 15.04 (
systemd 219) or later are compatible with
For other distributions, check the version of your
systemd before proceeding.
$ systemctl --version
It is relatively straightforward to switch from Network Manager to
systemd-networkd (and vice versa).
First, disable Network Manager service, and enable
systemd-networkd as follows.
$ sudo systemctl disable NetworkManager $ sudo systemctl enable systemd-networkd
You also need to enable
systemd-resolved service, which is used by
systemd-networkd for network name resolution. This service implements a caching DNS server.
$ sudo systemctl enable systemd-resolved $ sudo systemctl start systemd-resolved
systemd-resolved will create its own
resolv.conf somewhere under
/run/systemd directory. However, it is a common practise to store DNS resolver information in
/etc/resolv.conf, and many applications still rely on
/etc/resolv.conf. Thus for compatibility reason, create a symlink to
/etc/resolv.conf as follows.
$ sudo rm /etc/resolv.conf $ sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
To configure network devices with
systemd-networkd, you must specify configuration information in text files with
.network extension. These network configuration files are then stored and loaded from
/etc/systemd/network. When there are multiple files,
systemd-networkd loads and processes them one by one in lexical order.
Let's start by creating a folder
$ sudo mkdir /etc/systemd/network
Let's configure DHCP networking first. For this, create the following configuration file. The name of a file can be arbitrary, but remember that files are processed in lexical order.
$ sudo vi /etc/systemd/network/20-dhcp.network
[Match] Name=enp3* [Network] DHCP=yes
As you can see above, each network configuration file contains one or more sections with each section preceded by
[XXX] heading. Each section contains one or more key/value pairs. The
[Match] section determine which network device(s) are configured by this configuration file. For example, this file matches any network interface whose name starts with
enp3s2, etc). For matched interface(s), it then applies DHCP network configuration specified under
If you want to assign a static IP address to a network interface, create the following configuration file.
$ sudo vi /etc/systemd/network/10-static-enp3s0.network
[Match] Name=enp3s0 [Network] Address=192.168.10.50/24 Gateway=192.168.10.1 DNS=18.104.22.168
As you can guess, the interface
enp3s0 will be assigned an address
192.168.10.50/24, a default gateway
192.168.10.1, and a DNS server
22.214.171.124. One subtlety here is that the name of an interface
enp3s0, in facts, matches the pattern rule defined in the earlier DHCP configuration as well. However, since the file
10-static-enp3s0.network is processed before
20-dhcp.network according to lexical order, the static configuration takes priority over DHCP configuration in case of
Once you are done with creating configuration files, restart
systemd-networkd service or reboot.
$ sudo systemctl restart systemd-networkd
Check the status of the service by running:
$ systemctl status systemd-networkd $ systemctl status systemd-resolved
systemd-networkd also allows you to configure virtual network devices such as bridges, VLANs, tunnel, VXLAN, bonding, etc. You must configure these virtual devices in files with
Here I'll show how to configure a bridge interface.
If you want to create a Linux bridge (
br0) and add a physical interface (
eth1) to the bridge, create the following configuration.
$ sudo vi /etc/systemd/network/bridge-br0.netdev
[NetDev] Name=br0 Kind=bridge
Then configure the bridge interface
br0 and the slave interface
.network files as follows.
$ sudo vi /etc/systemd/network/bridge-br0-slave.network
[Match] Name=eth1 [Network] Bridge=br0
$ sudo vi /etc/systemd/network/bridge-br0.network
[Match] Name=br0 [Network] Address=192.168.10.100/24 Gateway=192.168.10.1 DNS=126.96.36.199
$ sudo systemctl restart systemd-networkd
You can use
brctl tool to verify that a bridge
br0 has been created.
systemd promises to be a system manager for Linux, it is no wonder something like
systemd-networkd came into being to manage network configurations. At this stage, however,
systemd-networkd seems more suitable for a server environment where network configurations are relatively stable. For desktop/laptop environments which involve various transient wired/wireless interfaces, Network Manager may still be a preferred choice.
For those who want to check out more on
systemd-networkd, refer to the official man page for a complete list of supported sections and keys.
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